Beam splitter for simultaneous measurement of two orthogonal field polarizations

Translated from Izmeritel'naya Tekhnika, No. 3, pp. 48–49, March, 1992.     

智能测斜仪的设计

采用三轴正交加速度传感器测量地球重力矢量和三轴正交磁强传感器测量地磁场矢量的测斜原理,推导出了倾斜角、方位角和工具面角的计算公式;从硬件和软件两方面对智能测斜仪进行了研究和误差分析,并对主要的误差源作了软件补偿;采用Delphi语言作为软件平台,利用多线程开发了地面监控程序.     

Digital holographic interferometry for simultaneous orthogonal radial vibration measurements along rotating shafts

A digital holographic interferometry setup used to measure radial vibrations along a rotating shaft is presented. A continuous Nd:YAG laser and a high-speed digital camera are used for recording the holograms. The shaft was polished optically smooth to avoid speckle noise from the rotating surface. The light reflected from the shaft was directed onto a diffuser which in turn was imaged by the holographic system. Simultaneous measurements with a laser vibrometer were performed at one point and comparisons between the signals showed good agreement. It is shown that different vibration components of a rotating shaft can be simultaneously measured with this technique.     

Design and analysis of a diffractive optical filter for use in an optoelectronic error-diffusion neural network

The design, fabrication, experimental characterization, and system-performance analysis of a diffractive optical implementation of an error-diffusion filter for use in digital image halftoning is reported. A diffractive optical filter was fabricated as an eight-level phase element that diffuses the quantization error nonuniformly in both the weighting and the spatial dimensions, according to a prescribed algorithm. Ten identical diffractive elements were fabricated on ten different wafers and subsequently characterized experimentally. A detailed error analysis including both fabrication and instrumentation errors was carried out to quantify the performance of the fabrication process as well as the expected system performance of the filters. Halftone system performance was evaluated by use of the experimental filter's performance and both quantitative and qualitative performance metrics. The results of this analysis demonstrate that multiple identical copies of a diffractive optical filter can be produced with sufficient accuracy that no loss in the halftoning system performance results.     

Fuzzy simultaneous measurement of two polarization vector components

The advent of quantum computers threatens the security of conventional encryption schemes (e.g., those based upon the excessive amount of computational time that might be required to guess your password). Quantum encryption is intended to restore the security by basing it instead upon the impossibility of the simultaneous measurement of two noncommuting operators. I derive a measurement associated with the angular momentum lowering operator, which describes a simultaneous (yet realizable) measurement of two noncommuting spin-vector components. Correlations between two such detectors are also discussed and compared with the conventional Stern-Gerlach results.     

Optical-fiber sensor for simultaneous measurement of pressure and temperature: analysis of cross sensitivity

The use of a highly elliptical core two-mode fiber for simultaneous measurement of pressure (radial pressure or hydrostatic pressure) and temperature is presented. The sources of errors are discussed. Expressions are developed to calculate the cross sensitivities. From the numerical examples, some useful conclusions are given.     

Polariscope for simultaneous measurement of the principal axis and the phase retardation by use of two phase-locked extractions

A novel polariscope with electro-optic modulation that is capable of simultaneous measurement of the principal axis and the phase retardation of an optical linear birefringent medium by means of two phase-locked extractions is described. A phase compensator is used to suppress the transmission phase-retardation effect of the beam splitter, thereby enhancing the precision of the measuring performance. The validity of the proposed design is demonstrated by measurement of the principal axis and phase retardation of a quarter-wave plate sample. There are absolute errors of 0.25 degrees on average and 0.58 degrees at maximum in the principal-axis measurement and of 0.75 degrees (0.83%) on average and 3.11 degrees at maximum in the phase-retardation measurement. Meanwhile, the retardation error lies within a 5% uncertainty range of a commercial wave plate. The root-mean-square resolutions for the principal-axis angle and phase-retardation measurements are 0.042 degrees and 0.081 degrees, respectively. Finally, the dynamic ranges of the principal-axis angle measurement and the phase-retardation measurement extend as far as 180 degrees.     

盘形凸轮廓线测量及逆向分析系统设计

基于逆向工程的思想提出了一种应用于盘形凸轮廓线的测量及分析系统,并详细介绍了该系统的设计原理、硬软件组成及测量数据的处理算法.通过实际测量并对测量数据按设计算法处理后表明,该系统的测量及分析方法正确,效果比较理想.利用所获得的有效数据在系统中添加后置CAD模块,建立凸轮的三维CAD实体模型,就可以很方便地进行数控机床加工.     

同步测量海水固有光学特性的高光谱剖面仪样机设计

基于双光路原理,研制出一种同步测量海水固有光学特性的高光谱剖面仪样机.样机用全反射管作测量吸收系数的样品池,全吸收管作测量衰减系数的样品池.使用高灵敏度的电荷耦合器(CCD)做光纤单色仪的光电探测器件,样机的光谱分辨率达到1.64nm.CCD信号的积分时间由复杂可编程逻辑器件(CPLD)和可编程计数器自动调整.用PC104微机自动控制数据采集和数据存储.存储数据由无线通信器件下载.室内实验验证了仪器测量的稳定性和可靠性.     

一种发射率测量系统的设计与实现

介绍了一种带有三个黑体空腔的发射率测量系统.该测量系统能在-10²00℃范围内测量多个样品的发射率.测量系统的硬件由三腔黑体辐射源、计算机、红外测温仪和导轨装置组成,可同时测量标准样品、待测样品、标准黑体辐射源三组温度数据,并计算得出待测样品的发射率.同时,应用编程语言进行测量系统的界面设计,结合软件和硬件搭建出了一个自动化、便捷的实验测量系统.     

A new method for simultaneous measurement of surface tension and viscosity

A new method for the simultaneous mesurement of the surface tension and viscosity of a liquid was developed by combining the principle of the oscillating drop method with a microgravity environment. This new method can be used in an ordinary laboratory. A droplet falls for 1.5 m in approximately 0.55 s. During this short period, the surface oscillation of the droplet is recorded by two high speed line sensors equipped with a laser backlight and cylindrical lenses. The recording speed and resolution of the line sensors are 84000 line/s and 2048 pixels, respectively. The laser backlight forms a shadow of the droplet, and each of the cylindrical lenses makes the shadow into be a line, allowing the maximum diameter to be precisely measured by a line sensor. Before focusing the laser column to a line, it was split into two columns and each of them is forcused into a different line in order to determine the changes in the diameters in two right-angled directions. The measured oscillations show only a single peak for the n = 2 mode in the Fourier spectrum. This fact guarantees that the surface oscillation is almost ideal, and the simple equations for a spherical droplet can be used without any corrections.     

An analysis of decohesion along an imperfect interface

A cohesive zone type interface model, taking full account of finite geometry changes, is used to study the decohesion of a viscoplastic block from a rigid substrate. The specific boundary value problem analyzed is a plane strain one with the imposed loading corresponding to overall uniaxial straining. The imperfection takes the form of a non-bonded portion of the interface. Dimensional considerations introduce a characteristic length into the formulation and the decohesion mode shifts from more or less uniform separation along the bond line to crack-like propagation as the ratio of block size to characteristic length increases. Field distributions prior to and accompanying propagation are displayed.     

Miniature all-fiber Fabry-Perot sensor for simultaneous measurement of pressure and temperature

This article presents a miniature, high-sensitivity, all-silica Fabry-Perot fiber-optic sensor suitable for simultaneous measurements of pressure and temperature. The proposed sensor diameter does not exceed 125 μm and consists of two low-finesse Fabry-Perot resonators created at the tip of an optical fiber. The first resonator is embodied in the form of a short air cavity positioned at the tip of the fiber. This resonator utilizes a thin silica diaphragm to achieve the sensor's pressure response. The second resonator exploits the refractive index dependence of silica fiber in order to provide the proposed sensor's temperature measurement function. Both resonators have substantially different lengths that permit straightforward spectrally resolved signal processing and unambiguous determination of the applied pressure and temperature.     

A scheme for the simultaneous measurement of atomic position and momentum

Abstract

We propose an optical scheme for the simultaneous measurement of the position and momentum of a single atom. The scheme involves the coupling of the atom of two light fields with different spatial and polarization characteristics. The proposed technique is closely related to the Arthurs-Kelly measurement scheme; the principal difference is that in the present case the values of the position and momentum are inferred from phase shifts in electromagnetic fields rather than from shifts in the position of a pointer.     

Temperature oscillation techniques for simultaneous measurement of thermal diffusivity and conductivity

Simple temperature ocillation techniques are described for the last measurement of thermal dill'usivity and conductivity of liquids. The liquid specimen is a slab bounded above and below by a reference material. Two Peltier elements mounted on the outer Surfaces of the reference layers generate temperature ocillationS of these surfaces. Temperature waves propagate tluough the reference layers into the specimen. The thermal dilhusivity of the specimen is deduced by measuring all evaluating the amplitude attenuation and or the phase shift between the fundamental temperature oscillations at the surface of the liquid specimen and at a well-defined position inside the specimen. If the thermal diffusivity of the specimen is known. the thermal conductivity is determined by the measured amplitude attenuation and or the phase shill between the fundamental temperature oscillations at the surface of the reference layer and at the surface of the specimen. Slab and semi-infinite body geometries are considered. Measurement cells are designed and experiments are carried out with water, ethanol. heptane. monane. and glycerine. The results of the measurements of thermal dilhusivity asree very well, and those of thermal conductivity reasonably well, with the data obtained from the literature.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19-24, 1994, Boulder, Colorado, U.S.A.Author to whom correspondence should be addressed.     

Acceleration measurement with an instrumented pen for signatureverification and handwriting analysis

Consideration is given to the problem of measuring the acceleration produced by hand-pen movements while one is signing with an accelerometer pen. Acceleration signals are characterized in terms of frequency, phase, and amplitude. This characterization makes possible the extraction from the accelerometer output those signal components relevant to the handwriting process. Electronic circuits are described which automatically extract these components and obtain a fully characterized handwriting acceleration signal     

Miniature endoscope for simultaneous optical coherence tomography and laser-induced fluorescence measurement

We have designed a multimodality system that combines optical coherence tomography (OCT) and laser-induced fluorescence (LIF) in a 2.0-mm-diameter endoscopic package. OCT provides approximately 18-microm resolution cross-sectional structural information over a 6-mm field. LIF spectra are collected sequentially at submillimeter resolution across the same field and provide histochemical information about the tissue. We present the use of a rod prism to reduce the asymmetry in the OCT beam caused by a cylindrical window. The endoscope has been applied to investigate mouse colon cancer in vivo.     

三维形貌测量中自动调焦系统的设计

在相移干涉显微镜中增加了自动调焦系统,使其快速获取高清晰干涉图像,提高了三维形貌的测量速度和测量精度。调焦系统采用图像自动调焦方法,分别以图像标准差函数和图像最大熵函数作为粗调函数和精调函数。实验表明本系统自动调焦范围扩大到150m,自动调焦精度为0.3m,调焦时间为4-8s。     

Low-coherence interferometer system for the simultaneous measurement of refractive index and thickness

We have developed a low-coherence interferometer system used for the simultaneous measurement of refractive index n and thickness t of transparent plates. Both the phase index n(p) and group index n(g) can be determined automatically in a wide thickness range of from 10 microm to a few millimeters. Two unique techniques are presented to measure n(p), n(g), and t simultaneously. One allows us to determine n(p), n(g), and t accurately by using a special sample holder, in which the measurement accuracy is 0.3% for the thickness t above 0.1 mm. In the other technique the chromatic dispersion delta n of index is approximately expressed as a function of (n(p) - 1) on the basis of measured values of n(p) and n(g) for a variety of materials, and then the simultaneous measurement is performed with a normal sample holder. In addition, a measurement accuracy of less than 1% is achieved even when the sample is as thin as 20 microm. The measurement time is also 3 min or more.